Carrier SINGLE PACKAGE ROOFTOP UNITS 48PG20-28 Installation And Service Instructions Manual

Also see for 48PG20---28: User's information manual User's information manual Controls, start-up, operation, service and troubleshooting instructions

Carrier SINGLE PACKAGE ROOFTOP UNITS 48PG20-28 Installation And Service Instructions Manual Manual pdf 60 page image

60Table 35 — IGC Board LED Alarm CodesLEGEND NOTES:1. There is a 3-second pause between alarm code displays.2. If more than one alarm code exists, all applicable alarm codes will bedisplayed in numerical sequence.3. Alarm codes on the IGC will be lost if power to the unit is interrupted.EconoMi$er IV TroubleshootingECONOMI$ER IV PREPARATION — This procedure isused to prepare the EconoMi$er IV for troubleshooting. Notroubleshooting or testing is done by performing the followingprocedure.NOTE: This procedure requires a 9-v battery, 1.2 kilo-ohmresistor, and a 5.6 kilo-ohm resistor which are not suppliedwith the EconoMi$er IV.1. Disconnect power at TR and TR1. All LEDs should beoff. Exhaust fan contacts should be open.2. Disconnect device at P and P1.3. Jumper P to P1.4. Disconnect wires at T and T1. Place 5.6 kilo-ohm resistoracross T and T1.5. Jumper TR to 1.6. Jumper TR to N.7. If connected, remove sensor from terminals SO and +.Connect 1.2 kilo-ohm 4074EJM checkout resistor acrossterminals SO and +.8. Put 620-ohm resistor across terminals SR and +.9. Set minimum position, DCV set point, and exhaustpotentiometers fully CCW (counterclockwise).10. Set DCV maximum position potentiometer fully CW(clockwise).11. Set enthalpy potentiometer to D.12. Apply power (24 vac) to terminals TR and TR1.DIFFERENTIAL ENTHALPY — To check differentialenthalpy:1. Make sure EconoMi$er IV preparation procedure hasbeen performed.2. Place 620-ohm resistor across SO and +.3. Place 1.2 kilo-ohm resistor across SR and +. The FreeCool LED should be lit.4. Remove 620-ohm resistor across SO and +. The FreeCool LED should turn off.5. Return EconoMi$er IV settings and wiring to normalafter completing troubleshooting.SINGLE ENTHALPY — To check single enthalpy:1. Make sure EconoMi$er IV preparation procedure hasbeen performed.2. Set the enthalpy potentiometer to A (fully CCW). TheFree Cool LED should be lit.3. Set the enthalpy potentiometer to D (fully CW). The FreeCool LED should turn off.4. Return EconoMi$er IV settings and wiring to normalafter completing troubleshooting.LEDFLASHCODEDESCRIPTION ACTION TAKEN BYCONTROL RESET METHOD PROBABLE CAUSEOn Normal Operation — — —Off Hardware Failure No gas heating. — Loss of power to the IGC. Check 5 amp fuse on IGC,power to unit, 24V circuit breaker, transformer, andwiring to the IGC.1 Flash Indoor Fan On/Off DelayModified5 seconds subtracted fromOn delay.5 seconds added to Offdelay (3 min max).Power reset. High temperature limit switch opens during heatexchanger warm-up period before fan-on delayexpires.High temperature limit switch opens within10 minutes of heat call (W) Off.See Limit Switch Fault.2 Flashes Limit Switch Fault Gas valve and igniter Off.Indoor fan and inducer On.Limit switch closed, orheat call (W) Off.High temperature limit switch is open. Check the oper-ation of the indoor (evaporator) fan motor. Ensure thatthe supply-air temperature rise is within the range onthe unit nameplate. Check wiring and limit switchoperation.3 Flashes Flame Sense Fault Indoor fan and inducer On. Flame sense normal.Power reset for LED reset.The IGC sensed a flame when the gas valve should beclosed. Check wiring, flame sensor, and gas valveoperation.4 Flashes Four Consecutive LimitSwitch FaultNo gas heating. Heat call (W) Off.Power reset for LED reset.4 consecutive limit switch faults within a single call forheat. See Limit Switch Fault.5 Flashes Ignition Fault No gas heating. Heat call (W) Off.Power reset for LED reset.Unit unsuccessfully attempted ignition for 15 minutes.Check igniter and flame sensor electrode spacing,gaps, etc. Check flame sense and igniter wiring. Checkgas valve operation and gas supply.6 Flashes Induced Draft Motor Fault If heat off: no gas heating.If heat on: gas valve Off andinducer On.Inducer sense normal, orheat call (W) Off. Inducer sense On when heat call Off, or inducer senseOff when heat call On. Check wiring, voltage, andoperation of IGC motor. Check speed sensor wiring toIGC.7 Flashes Rollout Switch Lockout Gas valve and igniter Off.Indoor fan and inducer On. Power reset. Rollout switch has opened. Check gas valve opera-tion. Check induced-draft blower wheel is properlysecured to motor shaft.8 Flashes Internal Control Lockout No gas heating. Power reset. IGC has sensed internal hardware or software error. Iffault is not cleared by resetting 24 v power, replace theIGC.9 Flashes Temporary Software Lockout No gas heating. 1 hour auto reset, orpower reset.Electrical interference is disrupting the IGC software.IGC — Integrated Gas Unit ControlLED — Light-Emitting DiodeIMPORTANT: Be sure to record the positions of all poten-tiometers before starting troubleshooting.